cocoa-touch

问题 Is there a way to determine if a class is suitable as a key and will work as you expect, for example I want to use NSIndexPath as a key in NSDictionary but I don't know for certain if two different NSIndexPath instances with the same integer values will always return the same hash value. 回答1: Apple's NSObject's isEqual document says: If two objects are equal, they must have the same hash value. This last point is particularly important if you define isEqual: in a subclass and intend to put

问题 Is there a way to determine if a class is suitable as a key and will work as you expect, for example I want to use NSIndexPath as a key in NSDictionary but I don't know for certain if two different NSIndexPath instances with the same integer values will always return the same hash value. 回答1: Apple's NSObject's isEqual document says: If two objects are equal, they must have the same hash value. This last point is particularly important if you define isEqual: in a subclass and intend to put

问题 OK, here's what I want to implement and I need your ideas : Input a geo location by name/address/etc (e.g. London, Oxford Street 20 ) Get the point's longitude/latitude My Questions : How would you go about that? Is using Google Maps API (that's what I first thought of) my only solution? It'd be better if the service used CAN be freely integrated in a commercial app - so any idea is welcome... :-) 回答1: There is a built in API for that. For iOS 5 and newer you can use CLGeocoder and for older

问题 I have a universal view controller class which all of the view controller classes in my app inherit from which has the following loadView method: - (void) loadView { if (viewType == UIStandardViewControllerViewTypeUIView) { UIView *view = [[UIView alloc] initWithFrame: [[UIScreen mainScreen] applicationFrame]]; [self setView: view]; [view release]; } else if (viewType == UIStandardViewControllerViewTypeUIScrollView) { UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame: [[UIScreen

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: display image from URL retrieved from ALAsset in iPhone In my Application I need to get specific image from Photo Library, with use of didFinishPickingMediaWithInfo i am able to get the Imagename and ImagePath. I am storing Imagename, ImagePath in Database. But, how to show that specific image with use of the Imagename or ImagePath in Imageview from Photo Library? 回答1: Please make use of ALAssetLibrary . To do

问题 Is it possible to change the 'gravity' (stop speed) when scrolling through a UIScrollView with paging enabled? I've implemented a horizontal UIScrollView that acts like the UIPickerView . I want to be able to scroll through many items based on the flick speed. Thanks! 回答1: Unfortunately there's no simple property you can change to achieve this, but you can use the scrollview delegate methods to roll your own (it is somewhat complex, but achievable - I've modified table views to 'snap' to rows

问题 I want to use a table view as the detail pane in my UISplitViewController. How do I put the toolbar at the top? I want to be able to add bar button items in the same way as my non-table detail views. Thanks. 回答1: My frustration with this problem lay in trying to use the UITableViewController class, which does not allow you to add other UI elements like a toolbar. I solved it by creating a UIViewController object and adding the toolbar and table view to its nib individually. I then had the

问题 I have successfully created a TabBar with two ScrollView-tabs. However, if i scroll to the bottom in one tab and then switch tab and then switch back, my content seem to have disappeared upwards. If i try to scroll to the top i get stuck in the middle of the content but the scrollview thinks im at the top. What i know so far: contentView.frame.origin.y - (contentView is my view that resides in the ScrollView). If i print this variable when scrolling the first time i get 0 in every printout. I

问题 I have successfully created a TabBar with two ScrollView-tabs. However, if i scroll to the bottom in one tab and then switch tab and then switch back, my content seem to have disappeared upwards. If i try to scroll to the top i get stuck in the middle of the content but the scrollview thinks im at the top. What i know so far: contentView.frame.origin.y - (contentView is my view that resides in the ScrollView). If i print this variable when scrolling the first time i get 0 in every printout. I

问题 The url to launch email and start a new email on an iphone is "mailto://someone@somwhere.com". I just want to launch the email app, dropping the user at the main menu, or inbox. "mailto:" starts composing a new blank email I've tried "mail:", "email:" and a few others. Is there no way to just launch the email app? 回答1: I don't think so, since the whole idea of the url schemes is to launch another app given some context in your own app. Watch a specific YouTube vid, write an email, etc. in